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Wanted: STEbus cards/information


New Member
Jan 14, 2007
Boston, MA
I have a box full of microprocessors (RC6512/6502, Z80, 6809, RCA 1802/1804) that I'd like to showcase in some way. Building a working system with them seems like the best option, since I'd like to share other peripherals across the CPUs - these include sound chips (AY-3-8910 and ymz284), video chips (TMS9918 and 1861/pixie) and other circuitry.

So I'm considering building an STEbus system. The STEbus (IEEE 1000-1987) uses 64 pins on an EuroCard (DIN 41612) connector, and allows up to 3 processors to serve as bus masters.

So I'm looking for STEbus interface examples and examples of cards. Keith Howell's site apparently had some examples, but it's no longer available.


Veteran Member
Dec 21, 2006
Hi Ralph! You could build some of the N8VEM boards. We have projects for the 6502, Z80, AY-3-8910, TMS9918, etc. The N8VEM boards are similar to STEbus in that they are Eurocard (160x100mm) and use DIN41612 connectors but are not signal compatible with STEbus. One builder did make an adapter board for STEbus.

All the hardware and software design information is available (free) on the wiki and mailing list. A RCA 1802/1804 board would be neat and I can help you make a PCB for everyone to enjoy. Please consider the N8VEM home brew computing project. I think you'll like it.

Thanks and have a nice day!

Andrew Lynch


New Member
Jan 20, 2012
I would like to revive this thread as I'm also seeking for any information and/or schematics for STEBus devices. I have two processor cards for STEBus (as far as I know) - one 286 and one 386 - that I would like to run. I almost have the manuals for the cards from their producer (DSP Design LTD) and fortunately have one break-out cable with various connectors (parallel, serial, CGA and some DB37, probably for floppy).
Running this cards alone will not be a big deal because they need only 5V and have CGA embedded, but making anything more can be problematic :).


New Member
Apr 29, 2012
Your request for revival on STEbus activity causes me to respond.

STEbus's architecture is simplictic and is of the industry accepted Eurocard format. A mated Eurocard connection enjoys a degree of imperviousness to dust/muck ingress much more so
than the open card edge connection as exists in other bus systems.

The STEbus strive was for it to be an improvement on the STDbus.

Instigator of STEbus activity can be attributed to GMT Electronics Ltd in Epsom, Surry, UK. GMT produced a plethora of Motorola based CPU cards and I/O cards.

Only UK based manufacturers promulgated STEbus. Arcom being the dominant with DSP Design a strong contender.

A journey through STEbus hardware/software design is therapeutic.